We found that function btf_dump__dump_type_data can be called by the
user as an API, but in this function, the `opts` parameter may be used
as a null pointer.This causes `opts->indent_str` to trigger a NULL
pointer exception.

Fixes: 2ce8450ef5a3 ("libbpf: add bpf_object__open_{file, mem} w/ extensible opts")
Signed-off-by: Xin Liu <liuxin350@huawei.com>
Signed-off-by: Weibin Kong <kongweibin2@huawei.com>
---
v1 -> v2: Use OPTS_GET to fix NULL pointer exceptions
v1: https://lore.kernel.org/bpf/20220914123423.24368-1-liuxin350@huawei.com/ 

 tools/lib/bpf/btf_dump.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c
index 627edb5bb6de..4221f73a74d0 100644
--- a/tools/lib/bpf/btf_dump.c
+++ b/tools/lib/bpf/btf_dump.c
@@ -2385,7 +2385,7 @@ int btf_dump__dump_type_data(struct btf_dump *d, __u32 id,
 	d->typed_dump->indent_lvl = OPTS_GET(opts, indent_level, 0);
 
 	/* default indent string is a tab */
-	if (!opts->indent_str)
+	if (!OPTS_GET(opts, indent_str, NULL))
 		d->typed_dump->indent_str[0] = '\t';
 	else
 		libbpf_strlcpy(d->typed_dump->indent_str, opts->indent_str,
-- 
2.33.0

Hello:

This patch was applied to bpf/bpf-next.git (master)
by Andrii Nakryiko <andrii@kernel.org>:

On Sat, 17 Sep 2022 16:48:09 +0800 you wrote:
> We found that function btf_dump__dump_type_data can be called by the
> user as an API, but in this function, the `opts` parameter may be used
> as a null pointer.This causes `opts->indent_str` to trigger a NULL
> pointer exception.
> 
> Fixes: 2ce8450ef5a3 ("libbpf: add bpf_object__open_{file, mem} w/ extensible opts")
> Signed-off-by: Xin Liu <liuxin350@huawei.com>
> Signed-off-by: Weibin Kong <kongweibin2@huawei.com>
> 
> [...]

Here is the summary with links:
  - [v2] libbpf: Fix NULL pointer exception in API btf_dump__dump_type_data
    https://git.kernel.org/bpf/bpf-next/c/7620bffbf72c

You are awesome, thank you!
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